Goal: The program goal is to train pre-doctoral and postdoctoral biostatisticians in statistical theory and methods as applied to environmental health sciences (EHS). This aim is addressed by an integrated collaboration between biostatisticians and toxicologists to provide: supervision by biostatisticians with extensive experience in the development of statistical methodology;interaction with researchers with extensive experience in human and animal studies;practical experience in the applications of statistical methodology to problems in toxicology by participating in consulting projects and attending colloquia;and, mentoring of trainees to assist in developing independent academic careers. Training: This Training Program is collaboration between the Departments of Biostatistics and Computational Biology (DBCB), the Environmental Health Sciences Center, and the Department of Community and Preventive Medicine. The DBCB offers a Ph.D. degree in Statistics with an option in Biostatistics. The Department, created to foster biostatistical research and collaboration with researchers in the Medical Center, provides the administrative leadership and the critical link with the toxicologists. Trainees will be matched with a biostatistician as primary preceptor and a toxicologist as a secondary cosponsor. The EHS Biostatistics Training Grant Committee will review the progress of the trainees and the program. Trainees: Pre-doctoral trainees will have completed a baccalaureate degree with a major in mathematics, statistics, or a science major with a strong minor in mathematics or statistics. Selection is based on academic record, GRE scores, and recommendations. Pre-doctoral trainees must fulfill the standard requirements for the Ph. D. degree in statistics plus additional courses in biostatistics, epidemiology and toxicology. Two pre-doctoral four-year awards will be granted. Postdoctoral trainees must have completed a Ph. D. in statistics, mathematics or a related discipline, or a Ph. D. in toxicology. Each postdoctoral trainee will enroll in appropriate courses, attend seminars, and work with faculty mentors on biostatistics research and specific toxicology related projects. Two postdoctoral traineeships are awarded to establish an alternating two-year program. BACKGROUND This application is for continuation of a Training Program in Biostatistics as applied to Environmental Health Sciences administered through the Department of Biostatistics and Computational Biology (DBCB) at the University of Rochester. This Training Program was initially funded in 1991. Support is requested for two pre-doctoral students and two postdoctoral students. All students in the School of Medicine and Dentistry (in which the DBCB is located) are fully supported (tuition plus stipend) by the School of Medicine and Dentistry Graduate School Office for the first two years of their studies. So the requested support will partially support the trainees in their advanced years of study. The institutional environment for a training grant in environmental health biostatistics is outstanding. The DBCB has a strong tie with the Department of Environmental Medicine which has a distinguished history of research focused on human health risks from environmental contaminants. A success story from this training grant involves the Seychelles study data. One of the primary researchers in the Seychelles study is Dr. Huang who began her work with the study as a trainee from this program. She is now Associate Professor in the DBCB, is independently funded, and is a training faculty member of this program.